Bi-modal ionomers

ABSTRACT

The present invention relates to compositions and preparative process of partially or fully neutralized mixtures of carboxylate functionalized ethylene high copolymers or terpolymers (Mw between 80,000 and 500,000) with carboxylate functionalized ethylene low copolymers (Mw between 2,000 and 30,000) and organic acid salts and injection or compression molded applications such as golf ball components thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 10/376,969, filed on Feb. 28, 2003, now U.S. Pat. No. 6,762,246,which in turn is a divisional application of U.S. application Ser. No.09/924,194, filed on Aug. 8, 2001, now issued as U.S. Pat. No.6,562,906, which in turn claims priority under 35 U.S.C. § 119(e) toU.S. Provisional Appln. No. 60/224,668, filed on Aug. 11, 2000, and toU.S. Provisional Appln. No. 60/279,023, filed on Mar. 27, 2001. Each ofthe above identified applications is incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to partially or fully neutralized mixturesof carboxylate functionalized ethylene copolymers or terpolymers (Mwbetween 80,000 and 500,000) with carboxylate functionalized ethylene lowcopolymers (Mw between 2,000 and 30,000). It also relates to the use ofsuch ionomeric compositions in injection or compression moldedapplications such as golf ball components.

2. Description of Related Art

There is a need for highly resilient thermoplastic compositions thathave good processibility without loss of properties or improvedproperties (improved resilience and lower stiffness) without loss ofprocessibility.

There is a need in the golf ball art for balls that have a highresilience at high speed impact such as when struck by a driver andlower resilience at low speed impact such as when struck with a putter.High resilience at high speed impact would allow longer driving distancewhile lower resilience at low speed would provide better puttingcontrol.

BRIEF SUMMARY OF THE INVENTION

The highly resilient thermoplastic compositions of this inventionprovide improved balance of properties and processibility. Also, basedon testing of spheres, they appear to be useful as compositions in golfball applications, particularly as cover and/or intermediate layermaterial or as core and/or center material or as a one-piece ball, toachieve high resilience at high impact speed and relatively lowerresilience at lower impact speed.

The thermoplastic compositions are partially or fully neutralized“bi-modal blends” of high copolymers/low copolymers. That is to say,they are melt-blends of ethylene α,β ethylenically unsaturated C₃₋₈carboxylic acid copolymers having weight average molecular weights (Mw)of about 80,000 to about 500,000 (high copolymers) with ethylene α,βethylenically unsaturated C₃₋₈ carboxylic acid low copolymers having Mwof about 2,000 to about 30,000 (low copolymers). The high copolymers maybe blends of high copolymers and the low copolymers may be blends of lowcopolymers.

It has been found that, by proper selection of the low copolymer (AC540has been found to be particularly useful), the thermoplasticcompositions of this invention have demonstrated both enhanced meltprocessibility and enhanced heat stability. This combination of theproperty enhancements is contrasted to the reduction in heat stabilitythat would be expected with higher melt flows. These unique bi-modalionomer compositions are highly useful to the injection moldingapplications, including golf ball, foot wear, etc.

Further, with this proper selection of the low copolymer, thethermoplastic compositions of this invention are expected to haveenhanced abrasion and scuff resistance. This property enhancement,together with the other property improvements described above, would behighly useful to injection molding, films applications, including golfball, packaging films, flooring, protective coating, etc.

Preferably the weight percent high copolymer is about 50 to about 95 wt.% and the weight percent low copolymer is about 5 to about 50% based onthe total weight of the high copolymer and the low copolymer. Preferablyabout 40 to 100%, alternatively about 50 to about 85%, of the acidmoieties are neutralized by alkali metal or alkyline earth metalcations.

Optionally, the composition may contain up to 100 parts by weight oforganic acid salts, up to 200 parts by weight thermoplastic elastomers,up to 170 parts by weight fillers based on 100 parts by weight of the“bi-modal” ionomer of high copolymer/low copolymer be blend.

The compositions described above or their blends could be applied inbroad end-uses applications, including injection molding applications,golf ball applications, etc. More specifically the compositionsdescribed above are most suited for golf ball applications such as thecover, intermediate layers, core, and center of 2- or multiple-pieceballs, and as thermoplastic 1-piece balls.

BRIEF DESCRIPTION OF FIGURES

FIGS. 1 through 6 are plots of coefficient of restitution versus impactspeed for the individual bi-modal ionomers and the base ionomers used inExamples 23 through 28, respectively.

FIG. 7 is a plot of the data from Examples 23 though 29 depicting thedifferences in COR at the three velocities determined by subtracting theCOR of the base ionomer from the COR of the bi-modal ionomer in eachcase.

FIG. 8 is a plot of resilience versus impact speed of neat spheres basedon blends with or without the bi-modal ionomers.

FIG. 9 is a plot of the relative COR differences at different impactvelocities between the bi-modal ionomer, i.e. BMI-1 or BMI-2, containingblends and the reference ionomer blend, i.e.ionomer-1/ionomer-2 (50:50by weight).

DETAILED DESCRIPTION

All references disclosed herein are incorporated by reference.

“Copolymer” means polymers containing two or more different monomers.The terms “bipolymer” and “terpolymer” mean polymers containing only twoand three different monomers respectively. The phrase “copolymer ofvarious monomers” means a copolymer whose units are derived from thevarious monomers.

“Low copolymer” is used herein to differentiate the lower Mw materials,those with Mw of about 2,000 to about 30,000, from the higher Mw highcopolymers, those with Mw of about 80,000 to about 500,000.

“High copolymer” is used herein to differentiate the higher Mwmaterials, those with Mw of about 80,000 to about 500,000, from thelower Mw low copolymers, those with Mw of about 2,000 to about 30,000.

“Mw” means weight average molecular weight. “Mn” means number averagemolecular weight.

“Bi-Modal Blends” means blends of high copolymers and low copolymerswherein the Mw of the high copolymer and the Mw of the low copolymer aresufficiently different that two distinct molecular weight peaks can beobserved when measuring Mw of the blend by GPC with high resolutioncolumn.

“Ethylene (meth) acrylic acid” means ethylene acrylic acid and/orethylene methacrylic acid. Thus, the shorthand notation “E/(M)AA” usedto identify, describe and/or claim a copolymer means ethylene acrylicacid and/or ethylene methacrylic acid copolymer wherein “(M)” denotes“(meth)” and “AA” denotes “acrylic acid”.

According to the present invention, ethylene α,β ethylenicallyunsaturated C₃₋₈ carboxylic acid high copolymers, particularly ethylene(meth)acrylic acid bipolymers and ethylene, alkyl (meth)acrylate,(meth)acrylic acid terpolymers, having molecular weights of about 80,000to about 500,000 are melt blended with ethylene α,β ethylenicallyunsaturated C₃₋₈ carboxylic acid low copolymers, particularly ethylene(meth)acrylic acid low copolymers (more particularly the bipolymers), ofabout 2,000 to about 30,000 by methods well known in the art.

Preferably the Mw of the high copolymers is separated from the Mw of thelow copolymers sufficiently that the peaks for the high copolymers aredistinctly separated from the peaks for the low copolymers when theblend molecular weight distribution is determined by GPC with highresolution column. Preferably, high copolymers with lower Mw's areblended with low copolymers with lower Mw's (e.g. high copolymers withMw of 80,000 with low copolymers with Mw of 2,000). This becomes lessimportant as the Mw's of the high copolymers increase.

Preferably the low copolymers are present in the range of about 5 toabout 50 weight percent based on the total weight of the high copolymersand the low copolymers in the blend.

Preferably the high copolymers and low copolymers are partially or fullyneutralized by alkali metal or alkyline earth metal cations. Preferably,about 40 to about 100%, alternatively about 50 to about 85%,alternatively about 50 to about 90%, alternatively about 60 to about 80%of the acid moieties in the high copolymers and low copolymers areneutralized. Cations are lithium*, sodium*, potassium, magnesium*,calcium, barium, lead, tin, or zinc* (*=preferred), or a combination ofsuch cations.

Neutralization can be effected by first making an ionomer of the highcopolymer and/or of the low copolymer and then melt-blending them. Toachieve desired higher or full neutralization the resulting blend ofionomers can be further neutralized. Preferably the high copolymers andlow copolymers are melt-blended and then neutralized in situ. In thiscase desired higher or full neutralization can be achieved in one step.

Optionally, the composition may contain up to 100 parts by weight oforganic acid salts, up to 200 parts by weight thermoplastic elastomers,up to 170 parts by weight fillers based on 100 parts by weight of the“bi-modal” ionomer of the high copolymer/low copolymer blend. Otheradditives such as stabilizers and processing aids can be included.

The components of the blends of the present invention are more fullydescribed below.

High Copolymers

The high copolymers of this invention are preferably ‘direct’ acidcopolymers (as opposed to grafted copolymers) having an Mw of about80,000 to about 500,000. Preferably they have polydispersities (Mw/Mn)of about 1 to about 15.

They are preferably alpha olefin, particularly ethylene, /C₃₋₈ α,βethylenically unsaturated carboxylic acid, particularly acrylic andmethacrylic acid, copolymers. They may optionally contain a thirdsoftening monomer. By “softening”, it is meant that the polymer is madeless crystalline. Suitable “softening” comonomers are monomers selectedfrom alkyl acrylate and alkyl methacrylate, wherein the alkyl groupshave from 1-12 carbon atoms, and vinyl acetate.

The ethylene acid copolymers can be described as an E/X/Y copolymerswhere E is ethylene, X is the α,β ethylenically unsaturated carboxylicacid, and Y is a softening comonomer. X is preferably present in 2-30(preferably 5-25, most preferably 8-20) wt. % of the polymer, and Y ispreferably present in 0-35 (alternatively 3-25 or 10-25) wt. % of thepolymer.

The ethylene-acid copolymers with high levels of acid (X) are difficultto prepare in continuous polymerizers because of monomer-polymer phaseseparation. This difficulty can be avoided however by use of “co-solventtechnology” as described in U.S. Pat. No. 5,028,674 which isincorporated herein by reference or by employing somewhat higherpressures than those at which copolymers with lower acid can beprepared.

Specific acid-copolymers include ethylene/(meth) acrylic acidbipolymers. They also include ethylene/(meth) acrylic acid/n-butyl(meth) acrylate, ethylene/(meth) acrylic acid/iso-butyl (meth) acrylate,ethylene/(meth) acrylic acid/methyl (meth) acrylate, and ethylene/(meth)acrylic acid/ethyl (meth) acrylate terpolymers.

Examples of high copolymers and their molecular weights are shown in thefollowing table.

Mn Mw Polydispersity Composition/MI (10³) (10³) (Mw/Mn)E/23.5nBA/9MAA/25MI 26.6 176.5 6.6 E/15MAA/60MI 17.6 112.4 6.4E/4MAA/3MI 31.7 365.5 11.5 E/5.8AA/1.5MI 31.5 162.1 5.1 E/9AA/10MI 24.3186.4 7.7 E/10MAA/500MI 16.0 84.0 5.3 E/10MAA/35MI 19.6 160.8 8.2Low Copolymers

The low copolymers of this invention are preferably ‘direct’ acidcopolymers having an Mw of about 2,000 to about 30,000. Preferably theyhave polydispersities (Mw/Mn) of about 1 to about 10. They arepreferably alpha olefin, particularly ethylene, /C₃₋₈ α,β ethylenicallyunsaturated carboxylic acid, particularly acrylic and methacrylic acid,copolymers. Preferably the acid moiety in these copolymers is about 3 toabout 25 (preferably 5-15, most preferably 5-10) wt. % of the polymer.

Often these low copolymers are referred to as acid copolymer waxesavailable from Allied Signal (e.g., Allied wax AC143 believed to be anethylene/16-18% acrylic acid copolymer with a number average molecularweight of 2,040, and others indicated in the following table with theirmolecular weights).

Mn Mw Polydispersity Composition/MI (10³) (10³) (Mw/Mn) AC540 E/5AA/575cps 4.3 7.5 1.7 Brookfield @ 140 C.** AC580 E/10AA/650 cps 4.8 26.0 5.4Brookfield @ 140 C.** AC5120 E/15AA/650 cps 3.0 5.2 1.7 Brookfield @ 140C.** **No MI data available; Brookfield data defined by Honeywell orformally Allied SignalIonomers

Ionomers of the high copolymers and of the low copolymers when madeseparately can be made by methods well known in the art. The degree ofneutralization and the acid level should be selected so that theresulting ionomers of the high copolymers and the ionomers of the lowcopolymers remain melt processible.

The bi-modal ionomers of high copolymer/low copolymer blends can be madeby melt blending the melt processible ionomers separately made and thenoptionally further neutralizing with same or different cations toachieve desired higher or full neutralization of the resulting blend ofionomers. Preferably the non-neutralized high copolymers and lowcopolymers are melt-blended and then neutralized in situ. In this casedesired higher or full neutralization can be achieved in one step.

In either case, the neutralization can be effected by alkali metal oralkaline earth metal cations. Such cations are lithium*, sodium*,potassium, magnesium*, calcium, barium, lead, tin, or zinc*(*=preferred), or a combination of such cations. Preferably the acidmoieties in the resulting bi-modal ionomer of the high copolymers andlow copolymers are partially or fully neutralized to a level of about 40to about 100%, alternatively about 50 to about 85%, alternatively about50 to about 90%, alternatively about 60 to about 80%.

Organic Acid Salts

The salt of organic acid of the present invention comprises the salts,particularly the barium, lithium, sodium, zinc, bismuth, chromium,cobalt, copper, potassium, strontium, titanium, tungsten, magnesium orcalcium salts, of fatty acids, particularly stearic, behenic, erucic,oleic, linoleic, Preferably, the fatty acid salt is selected to have thelowest volatility. It is chosen so as to maximize COR while minimizingstiffness or compression, which has often been called “PGA Compression”in the golf ball art.

Thermoplastic Elastomers

The thermoplastic polymer component of the invention is selected fromcopolyetheresters, copolyetheramides, elastomeric polyolefins, styrenediene block copolymers and thermoplastic polyurethanes, these classes ofpolymers being well known in the art.

The copolyetheresters are discussed in detail in patents such as U.S.Pat. Nos. 3,651,014; 3,766,146; and 3,763,109. They are comprised of amultiplicity of recurring long chain units and short chain units joinedhead-to-tail through ester linkages, the long chain units beingrepresented by the formula

and the short chain units being represented by the formula

where G is a divalent radical remaining after the removal of terminalhydroxyl groups from a poly (alkylene oxide) glycol having a molecularweight of about 400-6,000 and a carbon to oxygen ratio of about 2.0-4.3;R is a divalent radical remaining after removal of carboxyl groups froma dicarboxylic acid having a molecular weight less than about 300; and Dis a divalent radical remaining after removal of hydroxyl groups from adiol having a molecular weight less than about 250; provided said shortchain ester units amount to about 15-95 percent by weight of saidcopolyetherester. The preferred copolyetherester polymers are thosewhere the polyether segment is obtained by polymerization oftetrahydrofuran and the polyester segment is obtained by polymerizationof tetramethylene glycol and phthalic acid. Of course, the morepolyether units incorporated into the copolyetherester, the softer thepolymer. For purposes of the invention, the molar ether:ester ratio canvary from 90:10 to 10:90, preferably 80:20 to 60:40; and the shore Dhardness is less than 70, preferably less than about 40.

The copolyetheramides are also well known in the art as described inU.S. Pat. No. 4,331,786, for example. They are comprised of a linear andregular chain of rigid polyamide segments and flexible polyethersegments, as represented by the general formula

wherein PA is a linear saturated aliphatic polyamide sequence formedfrom a lactam or amino acid having a hydrocarbon chain containing 4 to14 carbon atoms or from an aliphatic C₆-C₉ diamine, in the presence of achain-limiting aliphatic carboxylic diacid having 4-20 carbon atoms;said polyamide having an average molecular weight between 300 and15,000; and PE is a polyoxyalkylene sequence formed from linear orbranched aliphatic polyoxyalkylene glycols, mixtures thereof orcopolyethers derived therefrom said polyoxyalkylene glycols having amolecular weight of less than or equal to 6,000 and n indicates asufficient number of repeating units so that said polyetheramidecopolymer has an intrinsic viscosity of from about 0.8 to about 2.05.The preparation of these polyetheramides comprises the step of reactinga dicarboxylic polyamide, the COOH groups of which are located at thechain ends, with a polyoxyalkylene glycol hydroxylated at the chainends, in the presence of a catalyst such as a tetra-alkyl ortho-titinatehaving the general formula Ti(OR)₄, wherein R is a linear branchedaliphatic hydrocarbon radical having 1 to 24 carbon atoms. Again, themore polyether units incorporated into the copolyetheramide, the softerthe polymer. The ether:amide ratios are as described above for theether:ester ratios, as is the shore D hardness.

The elastomeric polyolefins are polymers composed of ethylene and higherprimary olefins such as propylene, hexene, octene and optionally1,4-hexadiene and or ethylidene norbornene or norbornadiene. Theelastomeric polyolefins can be functionalized with maleic anhydride.

Thermoplastic polyurethanes are linear or slightly chain branchedpolymers consisting of hard blocks and soft elastomeric blocks. They areproduced by reacting soft hydroxy terminated elastomeric polyethers orpolyesters with diisocyanates such as methylene diisocyanate (MDI) ortoluene diisocyanate(TDI). These polymers can be chain extended withglycols, diamines, diacids ,or amino alcohols. The reaction products ofthe isocyanates and the alcohols are called urethanes and these blocksare relatively hard and high melting. These hard high melting blocks areresponsible for the thermoplastic nature of the polyurethanes.

Block styrene diene copolymers are composed of polystyrene units andpolydiene units. The polydiene units are derived from polybutadiene,polyisoprene units or copolymers of these two. In the case of thecopolymer it is possible to hydrogenate the polyolefin to give saturatedrubbery backbone segments. These materials are usually referred to asSBS, SIS or SEBS thermoplastic elastomers and they can also befunctionalized with maleic anhydride.

Fillers

The optional filler component of the subject invention is chosen toimpart additional density to the bi-modal ionomers or blends of themwith other materials. Preferred densities depend on the application. Ingolf balls, they will include densities in the range starting with thedensity of unfilled polymer to 1.8 gm/cc. Generally, the filler will beinorganic having a density greater than about 4 gm/cc, preferablygreater than 5 gm/cc, and will be present in amounts between 0 and about60 wt. % based on the total weight of the composition. Examples ofuseful fillers include zinc oxide, barium sulfate, lead silicate andtungsten carbide, tin oxide, as well as the other well knowncorresponding salts and oxides thereof. It is preferred that the fillermaterials be non-reactive or almost non-reactive with the polymercomponents described above when the ionomers are less than completelyneutralized. If the ionomers are fully neutralized, reactive fillers maybe used. Zinc Oxide grades, such as Zinc Oxide, grade XX503R availablefrom Zinc Corporation of America, that do not react with any free acidto cause cross-linking and a drop in MI are preferred, particularly whenthe ionomer is not fully neutralized.

Other Components

Other optional additives include titanium dioxide which is used as awhitening agent or filler; other pigments, optical brighteners;surfactants; processing aids; etc.

Uses of Composition in Golf Balls

The bi-modal ionomers of this invention are useful in combination withother materials in specific combinations which, in large part, will bedependent upon the application. The bi-modal ionomers may be substitutedfor one or more materials taught in the art at the levels taught in theart for use in covers, cores, centers, intermediate layers inmulti-layered golf balls, or one-piece golf balls. Sufficient fillerscan be added to one or more components of the golf ball to adjust theweight of the golf ball to a level meeting the limits set by thegolfer's governing authority. See, for example, U.S. Pat. Nos.4,274,637; 4,264,075; 4,323,247; 4,337,947, 4,398,000; 4,526,375;4,567,219; 4,674,751; 4,884,814; 4,911,451; 4,984,804; 4,986,545;5,000,459; 5,068,151; 5,098,105; 5,120,791; 5,155,157; 5,197,740;5,222,739; 5,253,871; 5,298,571; 5,321,089; 5,328,959; 5,330,837;5,338,038; 5,338,610; 5,359,000; 5,368,304; 5,810,678; 5,971,870;5,971,871; 5,971,872; 5,973,046; 5,810,678; 5,873,796; 5,757,483;5,567,772; 5,976,443; 6,018,003; 6,096,830; and WO 99/48569.

Three-Piece Golf Ball

As used herein, the term “three-piece ball” refers to a golf ballcomprising a center, a traditional elastomeric winding wound around thecenter, and a cover made from any traditional golf ball cover materialsuch as Surlyn® ionomer resin, balata rubber or thermoset/thermoplasticpolyurethanes and the like. These three-piece golf balls aremanufactured by well known techniques as described in U.S. Pat. No.4,846,910 for example. The bi-modal ionomer may be used in the cover orthe center of such balls in combination with other materials typicallyused in these components.

Two-Piece Golf Ball

As used herein, the term “two-piece ball” refers to a golf ballcomprising a core and a cover made from any traditional golf ball covermaterial as discussed above. These two-piece balls are manufactured byfirst molding the core from a thermoset or thermoplastic composition,positioning these preformed cores in injection molding cavities usingretractable pins, then injection molding the cover material around thecores. Alternatively, covers can be produced by compression moldingcover material over the cores. The bi-modal ionomer may be used in thecover or the core of such balls alone or in combination with othermaterials typically used in these components.

Multi-Layer Golf Ball

As used herein, the term “multi-layer ball” refers to a golf ballcomprising a core, a cover made from any traditional golf ball covermaterial, and one or more mantles between the core and the cover. Thesemulti-layer balls are manufactured by first molding or making the core,typically compression or injection molding a mantle over the core andthen compression or injection molding a cover over the mantle. Thebi-modal ionomer may be used in the cover, the one or more mantles orthe core of such balls alone or in combination with other materialstypically used in these components.

One-Piece Golf Ball

As used herein, the term “one-piece ball” refers to a golf ball moldedin toto from a thermoplastic composition, i.e., not having elastomericwindings nor a cover. The one-piece molded ball will have a traditionaldimple pattern and may be coated with a urethane lacquer or be paintedfor appearance purposes, but such a coating and/or painting will notaffect the performance characteristics of the ball. These one-pieceballs are manufactured by direct injection molding techniques or bycompression molding techniques. The bi-modal ionomer may be used in suchballs in combination with other materials typically used in these balls.

EXAMPLES AND COMPARATIVE EXAMPLES

The resins used in the examples were as follows:

Mn* Mw* Polydispersity* Composition/MI (E3) (E3) (Mw/Mn) AC540 E/5AA/500cps Brookfield 4.3 7.5 1.7 @ 140 C.** AC580 E/10AA/650 cps 4.8 26.0 5.4Brookfield @ 140 C.** AC5120 E/15AA/650 cps 3.0 5.2 1.7 Brookfield @ 140C.** HCP 1 E/23.5nBA/9MAA/25MI 26.6 176.5 6.6 HCP 2 E/8.3AA/17nBAIonomer-1 E/23.5nBA/9MAA, 51% Mg neutralized/1.1MI Ionomer-2 E/19MAA,37% Na neutralized/2.6MI Ionomer-3 E/11MAA, 37% Na neutralized/10MIIonomer-4 E/11MAA, 57% Zn neutralized/5.2MI Ionomer-5 E/15MAA, 53% Znneutralized/5.0MI Ionomer-6 E/15MAA, 51% Na neutralized/4.5MI *MW andMWD Comparison (by GPC) **No MI data available

Examples 1-6

Blends of E/9MAA/23.5nBA (HCP 1) and E/10AA (AC580) at 90:10 (Example 1)and 80:20 (Example 2) ratios were neutralized on a single screw extruderwith a Mg(OH)₂ concentrate into bi-modal ionomers with the level ofneutralization indicated in the following table. The ionomers of Example1 and Example 2 together with reference Ionomer-1 (Comparative Example3) were injection molded into spheres and tested for the golf ballproperties. Improved COR's are measured for the bi-modal ionomers overthe reference. When bi-modal ionomer of Example 1 was further modifiedwith Magnesium Stearate, dramatic property enhancements were achieved(Examples 4, 5 and 6).

Ex. 1 Ex. 2 Comp. Ex. 3 E/MAA/nBA, wt % 90 80 100 E/AA, wt % 10 20 0Nominal Neut., % 70 75 51 MI at 190° C. 1 1 1.1 PGA compression 86 90 58Drop Rebound, % 59.8 56.3 56.6 COR-125 0.671 0.670 0.644 COR-180 0.6280.628 0.596 Ex. 4 Ex. 5 Ex. 6 Ex. 1 Bi-modal 85 70 60 ionomer, wt. %MgSt., w % 15 30 40 MI at 190° C. 1.5 1.6 2.5 PGA compression 85 83 91Drop Rebound, % 68.3 75.2 77.1 COR-125 0.728 0.761 0.773 COR-180 0.6780.703 0.718

Examples 7-12

A pellet blend of 90 wt. % Ionomer-2 and 10 wt. % E/15AA (AC5120) wasmelt blended and neutralized in the presence of a specific amount ofNa₂CO₃ concentrate to a nominal neutralization level of 60% in a twinscrew extruder to achieve the bi-modal ionomer (BMI-2). A pellet blendof 90 wt. % Ionomer-1 and 10 wt. % E/10AA (AC580) was melt blended andneutralized in the presence of a specific amount of Mg(OH)₂ concentrateto a nominal neutralization level of 70% in a twin screw extruder toachieve the bi-modal ionomer (BMI-1). Ionomer blends were then preparedby melt blending on a twin screw extruder at 50:50 ratio the bi-modalionomers, i.e. BMI-2, BMI-1 and the conventional ionomers, i.e.Ionomer-2 and Ionomer-1. The base ionomers and blends depicted in thetable were injection molded into spheres and tested for the golf ballproperties. The resilience enhancement of the blends containing thebi-modal ionomers was clearly illustrated.

Ex. 7 Ex. 8 Ex. 9 Comp. Ex. 10 Ex. 11 Comp. Ex. 3 Comp. Ex. 12 BMI-2, wt% 50 50 — — 100 — BMI-1, wt % 50 — 50 — — — Ionomer-2 — — 50 50 — 100Ionomer-1 — 50 — 50 — 100 — MI 0.6 0.6 NA NA 0.6 1.1 2.0 Neat SphereProperty PGA 130 125 132 126 150 58 158 compression Drop 67.3 66.7 66.764.6 76 56.6 80.3 Rebound, % COR-125 0.707 0.697 0.689 0.671 0.740 0.6440.750 COR-180 0.659 0.651 0.640 0.621 0.692 0.596 0.693

Examples 13-18

Bimodal ionomers based on Na and Zn ionomers containing 11% MAA, i.e.Ionomer-3 and Ionomer-4, and E/10AA at 90:10 ratio were prepared on thetwin screw extruder under the blending/neutralization conditions similarto the above examples using a Na₂CO₃ concentrate or a ZnO concentrate.The base ionomers and the bi-modal ionomers were injection molded intospheres and tested for the golf ball properties. The bi-modal ionomersand their blends showed lower PGA compression and improved COR.

Comp. Comp. Comp. Ex. 13 Ex. 14 Ex. 15 Ex. 16 Ex. 17 Ex. 18 BMI-3 100 50BMI-4 100 50 Ionomer-3 100 50 Ionomer-4 100 50 Nominal 75 75 37 57 75 47Neut, % MI 1 2 10 5 1.8 NA PGA 130 134 146 139 134 146 Comp. Drop 67.759 64.5 60.4 66.3 66.7 Rebound, % COR-125 0.702 0.621 0.649 0.615 0.6910.669 COR-180 0.660 0.580 0.601 0.569 0.651 0.622

Examples 19-22

Blend of E/8.3AA/17nBA (HCP 2) and E/10AA (AC580) at 90:10 weight ratiowas neutralized on a single screw extruder with a Mg(OH)₂ concentrateinto a bi-modal ionomer with 2MI and a nominal neutralization level of63% (Examples 20). A reference (Comparative Example 19) was alsoprepared under the similar conditions to a nominal neutralization levelof 53% with HCP 2 alone. The ionomers are injection molded into spheresand tested for the golf ball properties. Improved COR's are measured forthe bi-modal ionomers over the reference. When bi-modal ionomers ofExample 20 were further modified with MgSt. (Examples 21 and 22)dramatic property enhancements were achieved.

Comp. Ex. 19 Ex. 20 Ex. 21 Ex. 22 MgSt. Mod., w % 0 0 15 40 MI 2 2 1.91.3 PGA Comp. 108 111 108 108 Drop Rebound, % 60.9 61.9 69.2 79.4COR-125 0.673 0.676 0.728 0.794 COR-180 0.631 0.636 0.686 0.745

Examples 23-29

Bi-modal ionomers of this invention achieve performance improvement overthe conventional base ionomer references in the relative relationshipbetween resilience and impact speed, i.e. high relative resilience athigh impact speed and lower relative resilience at low impact speed whencompared with conventional ionomer counterparts. This performancecombination is highly desirable in the golf ball application to enablegreater driving distance and better putting control.

COR Difference between BM Surlyn and Ref. Surlyn Example 23 ft/s 125ft/s 180 ft/s 23 BMI-3 - Ionomer-3 0.020 0.053 0.059 24 BMI-4 -Ionomer-4 −0.009 0.006 0.011 25 BMI-5*** - Ionomer-5 −0.008 0.016 0.02326 BMI-6**** - Ionomer-6 −0.022 −0.010 0.001 27 BMI-2 - Ionomer-2 −0.024−0.010 −0.001 28 BMI-1/20* - Ionomer-1 −0.002 0.026 0.032 29BMI-1/10** - Ionomer-1 0.021 0.027 0.032 *BMI-1/20: 80:20 blend ofionomer of HCP 1 and E/10AA (AC580) and further neutralized with Mg.**BMI-1/10: 90:10 blend of ionomer of HCP 1 and E/10AA (AC580) andfurther neutralized with Mg. ***BMI-5: Blend of ionomer-5 and E/15AA(AC5120) at 90:10 by weight and further neutralized with Zn. ****BMI-6:Blend of ionomer-6 and E/15AA (AC5120) at 90:10 by weight and furtherneutralized with Na.

FIGS. 1 through 6 are plots of coefficient of restitution versus impactspeed for the individual bi-modal ionomers and the base ionomers used inExamples 23 through 28, respectively. The impact speed of 23 feet/secondwas achieved by a drop rebound test (dropping sphere from a height of100 inches onto a hard, rigid surface such as a thick steel plate or astone block). The COR was then calculated from the impact velocitiesbased on the drop height and the rebound height measured. COR's at 125and 180 feet/second speeds were measured by firing the sphere from anair cannon at a velocity determined by the air pressure. The outboundvelocity generally employed is between 125 to 180 feet/second. The ballstrikes a steel plate positioned three feet away from the point whereoutbound velocity is determined, and rebounds through a speed-monitoringdevice. The return velocity divided by the outbound velocity is the COR.

FIG. 7 is a plot of the data in the table. It is a plot of thedifferences in COR at the three velocities determined by subtracting theCOR of the base ionomer from the COR of the bi-modal ionomer in eachcase.

FIG. 8 is a plot of resilience versus impact speed of neat spheres basedon blends with or without the bi-modal ionomers. The bi-modal stiffionomer and blends property characterization is provided in thefollowing table.

Bi-modal Stiff Ionomer and Blends Property Characterization Ionomer-2100 50 50 Ionomer-1 50 50 BMI-2 100 50 50 BMI-1 50 50 MI, g/10 min 2 0.6NA 0.6 NA 0.6 Neat Sphere Property PGA 158 150 126 125 132 130Compression Drop 80.3 76 64.6 66.7 66.7 67.3 Rebound, % COR-23 0.8960.872 0.804 0.817 0.817 0.820 (Calc) COR-125 0.75 0.74 0.671 0.697 0.6890.707 COR-180 0.693 0.792 0.621 0.651 0.64 0.659

FIG. 9 is a plot of the relative COR differences at different impactvelocities between the bi-modal ionomer, i.e. BMI-1 or BMI-2, containingblends and the reference ionomer blend, i.e.ionomer-1/ionomer-2 (50:50by weight). While the bi-modal ionomer containing blends exhibit higherCOR at higher impact velocities, they exhibit comparable COR at 23ft/second to allow good putting control, in combination with long drivedistance.

23 ft/sec 125 ft/sec 180 ft/sec COR at Different Impact SpeedsIonomer-2/Ionomer-1 0.804 0.671 0.621 BMI-2/Ionomer-1 0.817 0.697 0.651Ionomer-2/BMI-1 0.817 0.689 0.64 BMI-2/BMI-1 0.82 0.707 0.659 CORDifference Relative to Ionomer-2/Ionomer-1 Blend BMI-2/Ionomer-1 0.0130.026 0.03 Ionomer-2/BMI-1 0.013 0.018 0.019 BMI-2/BMI-1 0.016 0.0360.038

Examples 30 to 33

Bi-modal ionomers of this invention achieve performance improvement overthe conventional base ionomer references in the heat stability, asmeasured by the resistance to deformation at the elevated temperatureand under stress. E/9MAA/23.5nBA (HCP 1) was partially neutralized(about 51%) with Mg(OH)₂ concentrate on a single screw extruder and wassubsequently blended with E/5AA (AC540) at 90:10 (Example 30) and 85:15(Example 31) ratios and further neutralized with Mg(OH)₂ concentrate tomaintain approximately 51% neutralization.

E/9MAA/23.5nBA (HPC 1) was also partially neutralized (about 51%) withZnO concentrate on a single screw extruder and subsequently blended withE/5AA (AC540) at 90:10 (Example 32) and 85:15 (Example 33) ratios.

The bi-modal ionomers consistently demonstrated lower deformations thanthe conventional base ionomer references after subjecting to 70° C. and1 Newton force for 1400 minutes reflecting enhanced resistance to heatinduced deformation, i.e. heat stability. This performance enhancementis highly desirable in the golf ball application to enable ballstability when stored in hot environment under load.

Ex. Ex. Comp. Comp. Ex. 1 30 31 Ex. 3 Ex. 32 Ex. 33 Ex. 34** MI 1 1.82.7 0.95 0.48 0.77 0.28 % Deform.* 17.3 10.2 9.9 22.1 15 9.7 20.6*Deformation = % Height Change under 1 Newton/70° C. for 1400 minutes.**Resin used in Comp. Ex. 34: E/9MAA/23.5nBA/25MI about 51% neutralizedwith ZnO.

1. A cover of a golf ball comprising a bi-modal composition comprising athermoplastic composition that is melt processible consistingessentially of (a) E/X/Y copolymers where E is ethylene, X is derivedfrom a C3 to C8 α,β ethylenically unsaturated carboxylic acid, and Y isa softening comonomer selected from the group consisting of alkylacrylates and alkyl methacrylates, wherein the alkyl groups have from1-8 carbon atoms, or ionomers of the E/X/Y copolymers wherein X is about2-30 wt. % of the E/X/Y copolymer, and Y is 0 to about 35 wt. % of theE/X/Y copolymer; (b) 5-50 wt. % based on (a)+(b) of one or more E/(M)AAcopolymers having 3-25 wt. % (M)AA or salts thereof, wherein the E/X/Ycopolymers have an Mw in the range of 80,000 to 500,000, and the E/(M)AAcopolymers have an Mw between 2,000 and 30,000; and (c) 5-50 wt. % basedon (a)+(b) of one or more aliphatic, mono-functional organic acidshaving fewer than 30 carbon atoms or salt thereof, wherein greater than80% of all the acid of (a) and of (b) and of (c) is neutralized; whereinsufficient filler is added (to one or more components of the golf ball)to adjust the weight of the golf ball to a level meeting the limits setby the golfer's governing authority.
 2. An intermediate layer in amulti-layer golf ball comprising a bi-modal composition comprising athermoplastic composition that is melt processible consistingessentially of (a) E/X/Y copolymers where E is ethylene, X is derivedfrom a C3 to C8 α,β ethylenically unsaturated carboxylic acid, and Y isa softening comonomer selected from the group consisting of alkylacrylates and alkyl methacrylates, wherein the alkyl groups have from1-8 carbon atoms, or ionomers of the E/X/Y copolymers wherein X is about2-30 wt. % of the E/X/Y copolymer, and Y is 0 to about 35 wt. % of theE/X/Y copolymer; (b) 5-50 wt. % based on (a)+(b) of one or more E/(M)AAcopolymers having 3-25 wt. % (M)AA or salts thereof, wherein the E/X/Ycopolymers have an Mw in the range of 80,000 to 500,000, and the E/(M)AAcopolymers have an Mw between 2,000 and 30,000; (c) 5-50 wt. % based on(a)+(b) of one or more aliphatic, mono-functional organic acids havingfewer than 30 carbon atoms or salt thereof, wherein greater than 80% ofall the acid of (a) and of (b) and of (c) is neutralized; and,optionally, (d) 1-30 wt. % based on the total weight of the bimodalcomposition of thermoplastic elastomeric resin selected fromcopolyetheramides, copolyetheresters, elastomeric polymerolefins, blockpolystyrene polydiene copolymers, and thermoplastic urethanes; whereinsufficient filler is added (to one or more components of the golf ball)to adjust the weight of the golf ball to a level meeting the limits setby the golfer's governing authority.
 3. A core or part of a core of atwo- or multiple-piece golf ball or a center of a three-piece golf ballcomprising a bi-modal composition comprising a thermoplastic compositionthat is melt processible consisting essentially of (a) E/X/Y copolymerswhere E is ethylene, X is derived from a C3 to C8 α,β ethylenicallyunsaturated carboxylic acid, and Y is a softening comonomer selectedfrom the group consisting of alkyl acrylates and alkyl methacrylates,wherein the alkyl groups have from 1-8 carbon atoms, or ionomers of theE/X/Y copolymers wherein X is about 2-30 wt. % of the E/X/Y copolymer,and Y is 0 to about 35 wt. % of the E/X/Y copolymer; (b) 5-50 wt. %based on (a)+(b) of one or more E/(M)AA copolymers having 3-25 wt. %(M)AA or salts thereof, wherein the E/X/Y copolymers have an Mw in therange of 80,000 to 500,000, and the E/(M)AA copolymers have an Mwbetween 2,000 and 30,000; (c) 5-50 wt. % based on (a)+(b) of one or morealiphatic, mono-functional organic acids having fewer than 30 carbonatoms or salt thereof, wherein greater than 80% of all the acid of (a)and of (b) and of (c) is neutralized; and, optionally, (d) 1-30 wt. %based on the total weight of the bimodal composition of thermoplasticelastomeric resin selected from copolyetheramides, copolyetheresters,elastomeric polymerolefins, block polystyrene polydiene copolymers, andthermoplastic urethanes; wherein sufficient filler is added (to one ormore components of the golf ball) to adjust the weight of the golf ballto a level meeting the limits set by the golfer's governing authority.4. A one-piece golf ball comprising the a bi-modal compositioncomprising a thermoplastic composition that is melt processibleconsisting essentially of (a) E/X/Y copolymers where E is ethylene, X isderived from a C3 to C8 α,β ethylenically unsaturated carboxylic acid,and Y is a softening comonomer selected from the group consisting ofalkyl acrylates and alkyl methacrylates, wherein the alkyl groups havefrom 1-8 carbon atoms, or ionomers of the E/X/Y copolymers wherein X isabout 2-30 wt. % of the E/X/Y copolymer, and Y is 0 to about 35 wt. % ofthe E/X/Y copolymer; (b) 5-50 wt. % based on (a+(b) of one or moreE/(M)AA copolymers having 3-25 wt. % (M)AA or salts thereof, wherein theE/X/Y copolymers have an Mw in the range of 80,000 to 500,000, and theE/(M)AA copolymers have an Mw between 2,000 and 30,000; (c) 5-50 wt. %based on (a)+(b) of one or more aliphatic, mono-functional organic acidshaving fewer than 30 carbon atoms or salt thereof, wherein greater than80% of all the acid of (a) and of (b) and of (c) is neutralized; and,optionally, (d) 1-30 wt. % based on the total weight of the bimodalcomposition of thermoplastic elastomeric resin selected fromcopolyetheramides, copolyetheresters, elastomeric polymerolefins, blockpolystyrene polydiene copolymers, and thermoplastic urethanes; whereinsufficient filler is added to adjust the weight of the golf ball to alevel meeting the limits set by the golfer's governing authority.
 5. Anintermediate layer in a multi-layer golf ball comprising the compositionconsisting essentially of (a) E/X/Y copolymers where E is ethylene, X isderived from a C3 to C8 α,β ethylenically unsaturated carboxylic acid,and Y is a softening comonomer selected from the group consisting ofalkyl acrylates and alkyl methacrylates, wherein the alkyl groups havefrom 1-8 carbon atoms, or ionomers of the E/X/Y copolymers wherein X isabout 2-30 wt. % of the E/X/Y copolymer, and Y is 0 to about 35 wt. % ofthe E/X/Y copolymer, and (b) 5-50 wt. % based on (a)+(b) of one or moreE/(M)AA copolymers having 3-25 wt. % (M)AA or salts thereof, whereingreater than 80% of all the acid of (a) and of (b) is neutralized andwherein sufficient filler is added (to one or more components of thegolf ball) to adjust the weight of the golf ball to a level meeting thelimits set by the golfer's governing authority.
 6. A core or part of acore of a two- or multiple-piece golf ball or a center of a three-piecegolf ball comprising the composition consisting essentially of (a) E/X/Ycopolymers where E is ethylene, X is derived from a C3 to C8 α,βethylenically unsaturated carboxylic acid, and Y is a softeningcomonomer selected from the group consisting of alkyl acrylates andalkyl methacrylates, wherein the alkyl groups have from 1-8 carbonatoms, or ionomers of the E/X/Y copolymers wherein X is about 2-30 wt. %of the E/X/Y copolymer, and Y is 0 to about 35 wt. % of the E/X/Ycopolymer, and (b) 5-50 wt. % based on (a)+(b) of one or more E/(M)AAcopolymers having 3-25 wt. % (M)AA or salts thereof, wherein greaterthan 80% of all the acid of (a) and of (b) is neutralized, whereinsufficient filler is added (to one or more components of the golf ball)to adjust the weight of the golf ball to a level meeting the limits setby the golfer's governing authority.
 7. A one-piece golf ball comprisingthe composition consisting essentially of (a) E/X/Y copolymers where Eis ethylene, X is derived from a C3 to C8 α,β ethylenically unsaturatedcarboxylic acid, and Y is a softening comonomer selected from the groupconsisting of alkyl acrylates and alkyl methacrylates, wherein the alkylgroups have from 1-8 carbon atoms, or ionomers of the E/X/Y copolymerswherein X is about 2-30 wt. % of the E/X/Y copolymer, and Y is 0 toabout 35 wt. % of the E/X/Y copolymer, and (b) 5-50 wt. % based on(a)+(b) of one or more E/(M)AA copolymers having 3-25 wt. % (M)AA orsalts thereof, wherein greater than 80% of all the acid of (a) and of(b) is neutralized, and wherein sufficient filler is added to adjust theweight of the golf ball to a level meeting the limits set by the golfersgoverning authority.